Pushing Limits

Details of the failure of the No. 2 engine on a Qantas Airbus A380 show what can happen when we try to go higher, faster or bigger in engineering systems. The Trent 900 is a $15 million monster. It is tough and designed to withstand terrible abuse:

  • Losing a front blade:

What then caused this frightening result?

Rather than the anticipated failure due to bird-strike or metal fatigue, a more mundane oil-leak nearly caused disaster.
According to Rolls-Royce, a bearing box leaked oil into the engine, likely the compressor which is not designed to get hot but the oil could pass through to the combustion chamber and ignite heating up the components of the compressor causing larger parts than a blade to fail. It appears that a shaft failed releasing a whole disc at once breaking everything at once. A single blade failure is tolerable but this mess sent pieces of metal through the wing severing controls for the No. 1 engine preventing its shutdown when the emergency landing was made. Inspections on all the engines in use revealed several oil-leaks.

Pushing the limits on such engineering projects may distract engineers from the more mundane matter of retaining oil but fortunately this did not bring down the plane in the ocean which it could have done a short while later. Random pieces of metal flying about in a wing with a burning engine could have done real damage. The landing video shows that half the air-brakes did not work because half the dual control system was cut. Somehow they also lost control of the fuel for the No.1 engine. This was a very close thing. If the piece that punctured the wing had gone in to the cabin there could have been many casualties.

I am hopeful Roll-Royce will re-design the system not to leak and to improve fire detection/control so that this will not happen again. They will take a hit on sales no doubt because there is a competitive engine for the A380 from another company. Competition is good.

About Robert Pogson

I am a retired teacher in Canada. I taught in the subject areas where I have worked for almost forty years: maths, physics, chemistry and computers. I love hunting, fishing, picking berries and mushrooms, too.
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